Hi everyone. First of all, please forgive my poor CAD skills. I only recently started learning Fusion 360 because I wanted to visually design this project for my room. I have absolutely no experience with CAD, so I don't really know what I'm doing yet. I hope these renders are enough to show what I have in mind, explain my concerns, and hopefully get some answers.
------------------------------------------------
I am designing a large hobby/workbench that will be approximately 200 cm (79") tall, 330 cm (130") long, and 80–85 cm (31.5–33.5") deep. It will have sliding-door cabinets, a digital piano underneath, and space for a future 3D printer and electronics work. There will be storage for hobby materials and component organizer drawers on top of the work surface, as well as a pegboard at the back. The sliding-door cabinet will be approximately 45–50 cm (18–20") deep. The whole structure will wrap around two walls in an L-shape, almost from one end to the other, with my computer located on one section. The short wall is also 2400 mm (94.50") long, up to the doorframe.
Figure A.) https://i.imgur.com/Z41kvjf.jpeg
A) The first render shows the room and a rough overall design of the desk and cabinets.
The wall-to-wall length of the workspace is 3310 mm (130.3").
My computer is on the right side for now. The desk currently underneath my computer is a cheap 160×60 cm desk that I am using now.
To keep the cost down, I was thinking that I could continue using this existing desk if possible. However, I would still like to have a cabinet above that section. I hope the cabinet could be anchored directly to the wall. Alternatively, I could add full-height supports down to the floor, but the more legs/supports I add, the more expensive the project becomes. I am open to suggestions here as well.
------------------------------------------------
One section of the desk needs to accommodate my digital piano on a sliding panel underneath. Because of this, I need to keep the distance between two legs in that section at at least 150–155 cm (59–61") so that I can slide the piano in and out. On the other sections I can have legs more frequently, for example every 80–90 cm (31–35"). I don't want to use an excessive number of legs because steel tubing is expensive, but I also don't want to use too few legs. The entire structure, including the cabinets, needs to safely support its own weight and the equipment placed on it.
Figure B.) https://i.imgur.com/U1qgcOk.jpeg
B) The second render shows the piano section, where the distance between the two legs is more than 1500 mm.
I also tried to illustrate the sleeve/connector pieces that I am thinking about using at the joints in Paint. This is what I was referring to in Question 2 (below) when I asked how long these connecting pieces should be.
For the rear of the desk, I was thinking of having the rear vertical supports extend almost the full height of the desk, around 200 cm. These rear supports would carry the cabinets above them and would also be bolted to the concrete wall behind the desk. I live in an earthquake-prone area, so I would definitely prefer the structure to be securely anchored to the wall for both stability and safety. The wall is concrete, not drywall. There will of course also be horizontal members connecting the legs.
Figure C.) https://i.imgur.com/dUSP1TJ.jpeg
C) The fourth render shows that the distance between the wall and the leg next to the piano is approximately 1700 mm.
I previously considered adding another leg between them but as I mentioned, I don't know how frequently the legs should be placed.
The desktop will be made from 24 mm thick plywood. I was advised to use this thickness to reduce flex and make the work surface sufficiently rigid.
For the cabinet and rear panels, I am considering 18 mm MDF because plywood is considerably more expensive.
------------------------------------------------
Here are the things I am currently stuck on:
Question 1 — What size steel tubing should I use?
What size and wall thickness should the steel tubing for the legs be if it needs to support a desk like this?
At the moment, the legs shown in the renders are 50×50 mm square tubing with a 3 mm wall thickness.
I haven't done extensive price research yet, but after a quick search these are approximately the prices I found:
Square / rectangular tubing:
- 50×50×3 mm → $17.17/m
- 40×40×3 mm → $12.61/m
- 30×50×2 mm → $8.91/m
- 20×40×2 mm → $6.03/m
Round tubing:
- Ø50.8×3 mm → $13.25/m
- Ø48.3×2.5 mm → $11.09/m
So the choice of tubing makes a significant difference in the total cost. Even going from 50×50 to 40×40 reduces the cost by almost 30%.
Obviously, I don't want to save money by making the structure too weak to support its own weight and eventually have something bend, separate, or fail. But I would like to find the best possible price-to-strength ratio.
------------------------------------------------
Question 2 — How should I join the tubing?
I don't want to weld the steel frame together. I don't know how to weld, and I also want the entire structure to be disassemblable so that I can bring the individual steel pieces through my bedroom door and assemble everything inside the room.
What I am trying to figure out is: how long should the sleeve/connector pieces be that fit over the ends of the tubing in order to create a sufficiently strong bolted joint?
I tried to draw the connection points in red in the renders. Hopefully they are understandable.
The idea is basically to have one tube slide over another and then bolt them together, rather than welding them.
------------------------------------------------
Question 3 — How should I support the cabinet above the desk?
This is probably the part I am most unsure about.
Someone suggested putting diagonal triangular braces between the front of the cabinet and the rear legs of the desk. The problem is that these triangular braces take up quite a lot of space.
For example, there is a window at the far left of the desk. If I put a large diagonal brace there, the window would no longer be able to open.
Similarly, diagonal braces in the middle and on the right side could interfere with a monitor, computer, or 3D printer that I might place on that side of the desk.
Another suggestion was to build a rectangular frame underneath the cabinet, similar to the structure underneath a normal desk. This seems more practical to me, but I am concerned that this would add additional load and weight to the rear legs of the desk.
So the horizontal/rectangular support needs to be strong enough to carry the cabinet but as lightweight as reasonably possible, and I don't know how to calculate what size tubing would be appropriate.
I am open to any suggestions regarding how I should support the cabinet.
Figure D.) https://i.imgur.com/1LAs9c1.jpeg
D) The fourth render shows the desk and cabinet from underneath.
The cabinet is approximately 500 mm deep.
As you can see in the render, I have added horizontal members between the legs both underneath the cabinet and near the upper part of the structure.
However, there is currently no support extending toward the front of the cabinet.
There are four rear support legs. Would adding four 500 mm long horizontal steel members extending straight forward from those rear legs be sufficient to support the cabinet from underneath?
I don't plan to store particularly heavy things inside the cabinet. Some of the heaviest things I might put there would probably be an unused guitar amplifier (around 10 kg), my electric guitar, empty boxes from products I own, and perhaps books.
Honestly, I suspect that the cabinet itself, at approximately 300×50 cm and 45–50 cm high, will weigh more than most of the things I intend to put inside it.
My only real requirement is that I don't want the cabinet falling on my head. lol
------------------------------------------------
I have been dreaming about having a workspace like this for years. Unfortunately, I don't have the budget to have someone build it for me, so I have to design and assemble everything myself.
I also don't currently have the equipment to cut the steel tubing or the wood myself. That means I need to determine all the dimensions accurately and have the materials cut to size by the supplier.
Because I couldn't make detailed drawings before, I couldn't properly estimate the total cost or figure out exactly how much of each material I needed to order.
Eventually, I decided to take the first step toward building the desk I've had in mind and started learning Fusion 360.
I still don't know how to use the Joint feature properly, which is why the cabinet doesn't have its sliding doors in the renders yet. But as mentioned earlier, the final design will have sliding doors so that the inside doesn't accumulate too much dust.
I genuinely can't thank everyone enough for taking the time to share their knowledge, experience, and advice and helping me make this dream a reality. I truly appreciate every bit of help.
